US-born Susan Alexander-Max has made some good recordings
over the last decade for Naxos, from her three volumes of early sonatas
by Muzio Clementi (8.555808, 8.557695, 8.570475) to her Hummel chamber
works album (8.557694). More recently she received plaudits for her
all-clavichord recording of CPE Bach's half-brother Johann Christian
(review).

Her period instrument expertise finds itself applied to an early grand
piano for this recital of Bach's relatively well-known 'Prussian' Sonatas,
so called after their dedication to Crown Prince Friedrich of Prussia,
later to be Frederick the Great. Preserved in New York's Metropolitan
Museum of Art, this five-octave instrument dates back to the first decade
or two of proper 'harpsichord-case' grand piano design, completed in
Vienna around 1790 by Ferdinand Hofmann. One of its innovations is a
moderator that softens (muffles) the sound by means of knee-operated
levers - this can be heard in action on the very first track.

The Hofmann has a striking tone, a little twangy at times but robust
and bright, and Bach's Classically expressive music seems to thrive
on it. Alexander-Max notes the sense of "privilege" she feels in performing
on this valuable instrument, but it must be said that she does sound
rather restrained in these sonatas - almost as if she were afraid of
causing damage. Hers are somewhat perfunctory rather than compelling
accounts.

In any case, she can do nothing about the fact that Naxos's engineering
has had a rare misfire: potential buyers should be aware from the outset
that audio quality is compromised by a fairly faint but continuous noise,
resembling underwater whirring, that lies 'under' Alexander-Max's whole
recital. It is hardly conspicuous at the low volumes listeners are most
likely to set for such period music, but it is easily audible through
headphones at higher levels, and once the ear becomes aware of it, the
weirdness seems to leach through into the music itself. The in-house
reviewer for Naxos refers to "Reliable sound quality", a baffling remark
- but how this bizarrerie went unnoticed by so many before publication
is the biggest puzzle.

Pieter-Jan Belder's recording of the Prussian Sonatas for Brilliant
Classics came out around the same time as the Naxos (94320). Though
he performs on a combination of harpsichord and clavichord, which may
not be to all tastes, his immediately became one of the best accounts
available of these works - for Belder the notes disport where they seem
merely to trudge for Alexander-Max. For only a little more than the
price of a single Naxos CD, Brilliant include Belder's recording of
CPE's slightly later 'Württemberg' Sonatas, less frequently heard
than the Prussian cycle, but arguably more fulfilling.